Quality of care within the therapeutic community is an innovative research topic, and one that poses significant challenges given the complexity of treatment process in the therapeutic community. The goal of this study is to improve quality of care in the therapeutic community and will be achieved through three Specific Aims: Aim 1 - To refine and gather validity evidence for a client-level therapeutic community treatment process monitoring instrument by a.) evaluating measurement model and item performance invariance across specific client sub-populations (i.e., adults vs. adolescents; males vs. females; community vs. prison) and modes of administration (i.e., paper and pencil vs. computerized), b.) creating a shortened version of the process monitoring instrument that maintains the integrity and measurement precision of the original instrument, c.) examining the association between responses to the revised process monitoring instrument and program assessment of client treatment progress (time in treatment and treatment phase), controlling for client case-mix; Aim 2 - To validate the refined process monitoring instrument as a measure of treatment process by examining the change in client responses to the instrument over time, and the association between client responses and 1) specific proximal and distal client outcomes (e.g., treatment retention and abstinence) and 2) program activities and environment, controlling for client case-mix; Aim 3 - To examine how therapeutic community programs make use of information from a client-level process monitoring instrument within a continuous quality improvement framework that is designed to make incremental improvements in the quality of care provided and in subsequent client outcomes. This study, to be conducted with Phoenix House programs and treatment clients across the nation, is well-poised to enhance our understanding of therapeutic community treatment process within a quality of care framework and to demonstrate a promising model for implementing Continuous Quality Improvement approaches in therapeutic community and other substance abuse treatment programs.